The powder is for reducing the friction between the insulated cores and outer sheaths, often useful when you have to strip cables with multiple cores in a specific way. I've also seen it in some alarm cables, so this isn't restricted to just mains cords. It really depends on the surface area of the core insulation vs sheath insulation and up to the manufacturer, since this also stops the cores sticking to each other and improves the flexibility of the cable.
A lot of cables also have a string in them, it allows you to strip large sections of the sheath off cleanly reducing the risk of nicking the insulation of the cores. Very handy with cables like Cat6, though I've rarely seen this in mains and security cables.
It also improves heat transfer through the insulation, cooling it down better and perform a bit better keeping overheating insulation in shape.
The vagina is a self-cleaning system with a constant flow of mucus sweeping foreign objects like microbes, dirt or bacteria from the inside to the outside.
So are the lungs... yet asbestos (thanks!) is proven to cause lung cancer. As far as i understood it, the whole process is not fully researched, but so far those fibres themselves penetrate and tangle in tissue, are unable to be moved out by self cleaning processes the body has and do themselves not react with the tissue. Yet the bodys reaction to it means it gets coated in the remains of antibodies, the tissue scars and the regular irritation somehow causes the development of cancer. This can take 20 years, maybe less if there is constant exposure of asbestos, adding it up.
The skin is usually not affected, it probably does not penetrate deep enough and skin rubs off all the time, mucus membranes do not in that form (not all of it? at least not as effective).